Photoelectric transmitter



March 11, 1941:. L, M. POTTS PHbTOELECTRIC TRANSMITTER Filed Jan. '10,193B 2 Sheets-Sheet l FIG.

INVENTOR. LOU I S M. P0 T T S A ORNEY.

March 11, 1941. ,L. M. I=OTTS 2,234,532

PHOTOELECTRIC TRANSMITTER Filed Jan. 10, 1.938 2 Sheets-Sheet 2 I I46 Iv I42 .5 FIG. 8 I43 6| '32 g 7 I44 I37 l I I I I I I I I I I I I I I I II l l l l I I I l l INVENTOR. LOUIS M. POTTS F I G I 3 ATTORNEY.

Cil.

Patented Mar. 11, 1941 UNITED STATES 2.234.832 PHOTOELECTRIG TRANSMITTERLouis M. Potts, Evanston, Ill., assignor to Teletype Corporation,Chicago, 111., a corporation of Delaware Application January 10, 1938,Serial No. 184,138

37 Claims.

This invention relates to printing telegraph apparatus, and particularlyto keyboard controlled signal transmitting mechanism. I

An object of the invention is to generate telegraph signals in aphotoelectronic device through the cooperation of a distributorcontrolled from a keyboard.

Another object oi. the invention is to provide overlap between keyboardand distributor operations in a keyboard transmitter.

Briefly, the invention contemplates a keyboard mechanism including a setof code bars to be positioned characteristically according to the keylever depressed. Each of the code bars controls the correspondingpositionment of an apertured slide bar. A beam of light from a source ofi1- lumination is directed toward a photoelectronic device, andgenerally disposed in the path of the beam are the slide bars and twocoaxial cylinders which house the photoelectronic device. The wall ofthe inner cylinder contains a slot parallel to the axis of the cylinderand somewhat longer than the span of the slide bars, this slot being inthe light path.

The outer cylinder is rotatable under the control of a single revolutionclutch, and is provided with a'plurality of peripheral apertures sopositioned that they traverse the slot in the inner cylindersuccessively as the outer cylinder rotates. The apertures in the outercylinder are aligned with the slide bars and particularly with theapertures therein. The slide'bars rest on a stationary slotted member,and their range of movement is to position their apertures in or out ofregistry with the slot in the stationary member. When an aperture is inregistry, it permits a portion of the beam of light to impinge upon thesurface of the rotatable cylinder. Thereafter, as the peripheral slot ofthe rotatable cylinder, which is aligned with the particular slide bar,traverses the slot in the stationary cylinder, the beam of lighttransmitted through the aperture in the slide bar is also transmittedthrough the slots in the two cylinders and impinges upon thephotosensitive element. in the photocell, thus increasing theconductivity of the cell and generating a Signal impulse of a particularkind. When, however, the aperture in a slide bar is positioned out ofregistry with the slot in the stationary support, light is preventedfrom passing through the corresponding slot in the rotatable cylinder,and

the conductivity of the cell remains unchanged during traversal of theslot in the inner cylinder by the particular slot in the outer cylinder,thus generating a signal impulse of a different kind. The rotatablecylinder is released for one cycle of operation upon each depression ofa key lever and is arrested automatically at the end of the cycleinitiated by that key lever.

With regard to the arrangement of the light being set by the code bars,are locked during the cycle of rotation of the distributor, but aninstant after the start of the cycle, the code bars which had also beenlocked are unlocked and may be reset by the operation of another keylever. At the completion of the cycle of the distributor, the newsetting of the code bars is transferred to the slide bars by the yieldmechanism. A clutch release condition having been stored upon theoperation of the key lever to reset the code bars, the distributor isnot arrested but proceeds into the cycle contemplated by the resettingof the code bars.

According to another embodiment of the invention, the linkage betweenthe code bars and the slide bars includes no yield, so that when theslide bars are locked, the code bars are also locked, and they cannot bereset until the distributor closely approaches its rest position.

For a complete understanding of the invention and of the manner in whichthe same may be accomplished, reference may be had to the followingdetailed description to be interpreted in the light of the accompanyingdrawings wherein,

Fig. 1 is a perspective view of one embodiment of theinvention havingportions broken away to show structural details;

Fig. 2 is a side elevational View of the apparatus shown in Fig. 1;

Fig. 3 is a plan view of the apparatus shown in Fig. 2;

Fig. 4 is a perspective of one detail of the transmitter shown in Figs.1 to 3, inclusive;

Fig. 5 is a development of cylindrical scanning elements shown in Figs.1 to 3, inclusive;

Fig. 6 is a plan view of another embodiment of the invention;

Fig. 7 is a vertical sectional view taken approximately on the line 1-1of Fig. 6;

Fig. 8 is a diagrammatic showing of an electrical circuit;

Fig. 9 is an elevational view of the clutch tripping mechanism of theembodiment shown in Figs. 6 and 7;

Fig. 10 is an elevatlonal view partly broken away showing a modifiedkeyboard mechanism at one stage of operation; and

Fig. 11 is a view similar to Fig. 10 showing the same mechanism at alater stage of operation.

Referring now to the drawings in which corresponding referencecharacters designate identical parts throughout the several views andparticularly to Figs. 1 and 2, reference numeral H indicates a keyboardbase casting to the front of which is secured a slotted comb l2.Keylevers l3 extend through the slots in comb l2 to the interior ofkeyboard base casting H and are there pivotally supported on a commonpivot rod (not shown) and are spring urged to their uppermost positionswith respect to the slots in comb l2 by individual springs (also notshown). Each of the key levers I3 is provided with a keytop [4 by meansof which manual operation of the several key levers may be performed.

Inside the base casting II a plurality of code bars it are slidablysupported, Code bars l6 extend transversely ofthe keyboard mechanismdirectly below the entire set of key levers l3. The code bars areprovided at their upper edges with notches which may be defined by onevertical edge and one oblique edge or by two oblique edges, the notchingof the several code bars being variable with respect to the several keylevers in accordance with the code which, in the preferred embodiment ofthe invention, is a permutation code comprising various combinations ofmarking and spacing signals. Code bars I6 are slidable transversely ofthe keyboard base H from one to the other of two positions, and thesliding movement of the code bars is effected by the camming actionexerted by a key lever.l3 upon the oblique edge of a notch during theoperation of depressing the key lever. The notching of the code bars I6is such that for each permutational setting of code bars l6 by a keylever, no other key lever may be fully depressed, the reason for thisbeing that the simultaneous depression of two key levers involves theinconsistent condition of attempting to present at least one of the codebars in both of its possible positions.

Each of the code bars l6 supports on one face thereof a pair of spacedpins l1 between which is disposed the lower end of a lock lever it!which is pivotally mounted upon a pivot pin l9 intermediate the ends oflock lever l8. Keyboard base casting H is provided with a slot 2|through which the several lock levers l8 extend to be presented betweenthe pins ll carried by the corresponding code bars 86.

A universal ball 22 is contained within keyboard base casting i I andextends transversely thereof below all of the key levers I 3 and inclose proximity thereto. Universal bail 22 is pivotally supported at itsopposite ends upon pivot pins 23 and is provided near one end with abracket 24 which includes an arm 26 that pro- :Iects upwardly fromwithin the keyboard base I 6 through a slot 21. The purpose of universalbail 22 is to trip a distributor clutch, and the manner in which thismay be accomplished will be de scribed later. It may-be stated, however,at this point that upon the depression of any key lever I3, theuniversal ball 22 is rocked downwardly about its pivot pins 23, and theupper end of arm 26 which it supports is' thereby rocked outwardly.

Upon the upper surface of keyboard base It there is secured a bracket 3|the upper surface of which supports a plurality of flat slide bars 32.Each of the slide bars 32 is provided with a single aperture 33 which,when sliding ovement is imparted to slide bars 32. is movable into orout of registration with a narrow slot 34 in the upper part of bracket3|. Each of the slide bars 32 is articulated to an individual lever 36pivoted on pivot pin [9 adjacent to a corresponding one of the locklevers l8. The number of slide bars 32, levers 36, lock levers l8, andcode bars I6 is equal to the number of code elements involved in each ofthe permutation code combinations, which is preferably five, but whichmay, under conditions requiring a more extensive code. be six or more.Each of the levers 36 has reed springs 31 secured to the opposite edgesthereof, and the free ends of the reed springs are of sufficient widthto engage the edges of the slide bar operating lever 36 and also theedges of the adjacent and associated lock lever I8, as is clearlydisclosed in Fig. 4. Reed springs 31 are so ten-' sioned that they seekengagement with both edges of slide bar operating lever 33 andassociated lock lever l8, and it will be apparent from this that if alock lever is rocked upon pivot pin i9 while the associated slide baroperating lever 36 is held stationary, one of the reed springs 31 willbe moved by the lock lever out of engagement with the slide baroperating lever 36 which, in turn, will prevent the other reed springfrom following the motion of lock lever l8. A condition of unbalance isthus created as between the two springs 31, so that each spring seeks toshift the lever which it alone is engaging in such direction as torestore engagement of both springs to both levers. Thus, when therestraint upon the slide bar operating lever 36 is removed, it isimmediately shifted by one of the springs 31 in the same direction inwhich look lever l8 was rocked.

Keyboard base I I has secured to the upper surface thereof a cylindricalhousing 4| in which is slidably fitted a cylindrical support 42 for anelectric lamp 43. Within cylinder 4| are supported a spherical lens 44and cylindrical lens 45, the function of which is to focus an elongatedbeam of light from lamp 43 upon reflector 46, so positioned as toreflect the beam upwardly through elongated slot 34 in bracket 3|. Thefocusing of the beam upon the reflector may be accomplished by movingcylindrical lamp support 42 within cylinder 4i to vary the distancebetween lamp 43 and lens 44 and reflector 46, the latter beingstationarily supported.

Keyboard base ll supports, just forward of bracket 3!, a bracket 48which is provided near its upper end with a circular aperture ifitowhich is fitted, to be stationarily supported thereby, a cylinder 49having both ends open. Cylinder 49 is provided, in the lower portionthereof, with an elongated slot) 5| parallel to its a'tis and in avertical plane with respect to slot 34 in bracket 3|. Slot 5| is ofsufflcient length to span all of the slide bars 32 and to extend a shortdistance beyond the slide bars at one end. Slots 34 and 5! may be ofsubstantially the same length. On. its forward wall, bracket 48 supportsan adapter 52 which, in turn, supports the'base 53 of a photoelectronicdevice 54 that extends into stationary cylinder 49 and has its lightsensitive cathode 56 substantially coextensive with slots 34 and 5|.Upon the basis of the description thus far presented, it will beapparent that when any one of slide bars 32 is so positioned that itsaperture 33 is presented in the vertical plane defined by slots 34and'5l, light from lamp 43 will pass through condensing lens 44 and willbe directed by reflector 46 through slot 34, slide bar aperture ill ill

llll

amines and slot bl to impinge upon light sensitive cathode lit.Likewise, those of the slide bars 32 which have been so positioned,under the control ofloclr lever l8 and code bars is that their aperturesll are out of registry with slots 3t and bl, will intercept lighttransmitted through slot dd.

Keyboard base it supports electric motor ti to the rotor shaft of whichis secured pinion bl. llhis pinion meshes with a gear bl secured tosignal distributor shaft 64 which is rotatably supported in bearings 66carried by braclret t'l supported by keyboard base ll. Shaft tt hassecured thereto the driving element tl (Figs. 2 and 3) of a positivedrive single revolution clutch mechanism, the driven portion bl of whichis supported by shaft 64 but is not secured thereto, is urged bycompression spring ll into engagement with driving member W, and isnormally restrained from such engagement by clutch throw-out lever l2cooperating with clutch throw-out lug ll formed on the periphery ofdriven clutch member 69l Clutch throw-out lever lll is pivotallysupported at it and is urged by the tension spring I5 (Fig. 2) into thepath of clutch throw-out lug I3. When clutch throwout lever ll is rockedaway fromthe throw-out lug ill, compression spring ll urges drivenmemher llll into engagement with member bl whereby rotation is impartedto driven member ll from shaft Toward the end of a revolution, clutchthrow-out lever iii, if permitted to respond to the influence of itsbiasingspring, returns to its positionin the path of clutch throw-outlug ll, shifts driven clutch member 69 axially of shaft t l by acamrning actiomand thus adects disengagement of the clutch members andarrestment of driven member td.

lllrlven clutch member Ell, is slidably lreyed to a sleeve it which isalso supported by shaft t l. lit its forward end, sleeve l6 engages andsupports a cylinder ll which is closed at its rear most end, at whichpoint it is supported by sleeve lll, and which is open at its foremostend, the words foremost and rearmost as used herein be ing related tothe'front of the keyboard, the foremost and rearmost ends of cylinder llbeing the left and right ends, respectively, as viewed in Fig. 2.Cylinder ll is slightly larger than cylinder and is fitted over thelatter in coaxial relation with respect thereto and bears the samerelation; namely, coaxial, with respect to sleeve lit by which it issupported. It will be apparent from this that when sleeve 76 is rotatedupon the tripping of clutch throw-out lever ll, cylinder ll is alsorotated.

As indicated in Fig. ,1, and in complete detail in Fig. 5, cylinder llis provided with a plurality of circumferentially extending aperturesthat are oflset both axially andcircumferentially with respect to eachother successively. There is an aperture lid to correspond to each ofthe slide bars lit, and the slots 18 and mounting of cylinder ll aresuch that as cylinder W is rotated, each of the slots lid traverses theposition occupied by the aperture of the corresponding slide bar ll whenthe latter is presented in position to transmit light. In addition tothe slots it, cylinder fl is provided with a. slot it beyond therearm-ost of the slide bars 32 but within the range of slots lit and El,so that as cylinder ll is rotated, light may be transmitted invariablythrough slot is to cathode 56 of the photoelectric cell bl. It maybeadded that cylinder W is so mounted upon the sleeve It that when thelatter is in its rest position, due to the separation of the clutchelements tt and bl by clutch throw-out lever ll, slot "ll is in registrywith slots ll and bl so that light impinges continuously upon cathode htduring the rest interval. The blanll portion of cylinder ll between theend of slot ld and the beginning of the first of the slots lt providesfor the complete exclusion. of light from photoelectric cell ht during aportion of a cycle of rotation of cylinder ll.

Between the point at which cylinder fl is supported and the end againstwhich compression spring 'llvabuts, sleeve ld is provided with cams tiand hi. it loclr bail til pivotally supported upon screws ll hasintegral therewith an arm lt supporting at its free end a cam followerroller ll which-may engage cam dl. At their upper ends, the loot: leversit are provided with laterally exte'n'ding protections ll (rightwardlyas viewed in Fig. 3) each of which has an upstand ing loclring lug dd.The position of locking bail til with respect to lugs dd is such thatwhen a code bar is shifted to its extreme right-hand position, thusrocking its associated locking lever it to its extreme counterclockwiseposition, the locking lug ll of that'loclr lever is presented just tothe left (as viewed inldlg. 3) of loclr bail bl. When a code bar it isshifted to its extreme lefthand position which results in roclring ofits associated loclr lever it to its extreme clockwise position, theloclring lug llll of that loclr lever is presented just to the right ofloclr bail ll (also as viewed in Fig. ll). It will be apparent from thisthat when, after the setting of the code bars in particularpermutational positions by the depression of the lrey lever ll loclrbail til is lowered to present its loclrlng blade in the path ofmovement of inciting lugs til, none of the loclt levers can be roclredwhilethe loclr bail is thus lowered, and consequently none of the codebars it can be shifted and no other lrey lever can be depressed.

Loclr bail ill also has integral therewith an arm ll which, whenfollower roller d'l has been lifted to its'outermost position withrespect to cam ti, is engagedand held by a latch dl' secured to a sleeveill roclrably supported upon a stud t l. at

its opposite end, sleeve til has secured thereto a lever which has anarm llll engageable with a stop screw llt for limiting thecounterclockwise motionof lever tt, sleeve ll, and latch ll and whichalso has or depending arm til the lower end of which is disposed in thepath of a shoulder ill integral with a linlr ltl which is articulated atits forward end to arm lt carried by universal bail ll. Linlr ltl has aportion of its upper edge in an oblique plane adjacent to a screw ill-lcarried by a stationary braclret supported by lreyboard base ll. Tensionspring lll l supports linlr ltl so that its upper edge is in engagementwith screw ldll. When linlr ltll is moved forwardly by operation ofuniversal bail lb from a key lever it; its shoulder lll engages arm lllof lever db and imparts cloctzwise rotation thereto, l'his cloclrwiserotation is transmitted through sleeve til to latch arm, at which isalso roclred cloclrwise and permits arm ll to loclr bail til to escape.as linlr ltll is moved forwardly by the universal bail, it is alsoroclred downwardly by the camming action of screw ltl upon the obliquelydisposed portion of the upper edge so that the lower end of arm 99 oflever tt is permitted to escape from shoulder ldl, and lover db andlatch llll are restored to their normal or extreme countercloclrwisepositions by their biasing tension spring (not shown). The surface orlink ltl' immediately to llll the rear of shoulder IOI slopes downwardlyaway from the shoulder, so that as the universal bail 22 returns to itsnormal position and link I02 is moved rearwardly, it is rockeddownwardly about the point of articulation with arm 26 by the cammingaction of the lower end of arm 39 of lever 96 upon the sloping surfaceadjacent to shoulder mi, and shoulder IOI is thus restored to itsposition behind the lower end of arm 99 in which position it is preparedto rock lever 96 and latch 92 clockwise in response to the nextoperation of universal ball 22.

Looking bail 83 is also provided with a laterally extending projectionI06 from which depends an arm E01 terminating directly above an arm I08integral with clutch throw-out lever 12 and extending rightwardlytherefrom (as viewed in Fig. 3). The relationship of depending arm 501to clutch throw-out lever arm I08 is such that when arm 9| of lock bail83 is engaged and held by latch 92, the lower end of arm I01 is heldlifted sufficiently to permit the clutch throw-out lever to be presentedagainst the periphery of driven clutch member 69 in position to engageclutch throw-out lug 13 and effect disengagement of the clutch. Whenlock bail lever arm 9| escapes from latch 92 due to operation of linkI02 by universal bail 22, arm I01 depresses arm I08 of clutch throw-outlever 12 as lock bail 83 descends to locking relation to lock levers I8,and as clutch throw-out lever arm I08 is depressed, the clutch throw-outlever is rocked out of engagement with lug 13 and engagement of clutchelements 68 and 69 through the action of compression spring 1| iseffected. The restoration of arm 9| to latched condition, which isaccompanied by the lifting of ball 83 out of the path of movement oflugs 89 carried by lock levers I8, is effected by cam 8|, having asingle apex (not shown). This apex,

when clutch driven member 69 and its associated cam 8| by latch 92, andthat upon rocking of latch 92 by link I02, lock bail 83 immediately isrocked into locking position under the influence of its biasing tensionspring I09, and at the same instant clutch throw-out lever 12 is trippedby arm I01.

' Another lock bail, designated by the reference numeral III, is alsopivoted on pivot screws 84 and is so positioned with respect toupstanding lugs 2 carried by leftwardly extending projections H3 ofslide bar operating levers 36 (as viewed in Fig. 3) that the lugs N2 ofthose slide bar levers 36 that are rocked into extreme counterclockwisepositions are presented to the left of the locking blade of lock bailIII, and the lugs II2 of those slide bar levers that are rocked to theirextreme clockwise position are presented to the right of lock bail III.Lock bail III has integral therewith an arm II4 which is provided with acam follower roller I I6 which continuously engages cam 82. In the restcondition of the apparatus, follower roller II 6 engages the descendingslope of the single apex (not shown) of cam 82 slightly below theuppermost portion of that slope so that look bail III is held out oflocking relation to the lugs I|2 of slide bar controlling levers 36, andas bail III is biased into engagement with cam 82 by a tension spring 1,it applies a torque to cam sleeve 16 and therefore to driven clutchmember 69, which is slidably keyed to it, whereby the clutch elementsare maintained fully separated, so that the chattering of the clutchteeth is prevented. As sleeve 16 begins to rotate in response to thetripping of clutch throw-out lever 12, cam follower roller IIG descendsto the nadir portion of cam 82, and bail III is thus lowered intolocking relation to the slide bar operating levers 36.

The function of bail III is to lock the slide bars 32 in whateverpositions they may have been set, so that their setting shall not bedisturbed during the scanning of slot 5| in stationary cylinder 39 byrotating cylinder 11. It is, therefore, desirable that bail I shall belowered before that portion of slot 5| that is coextensive with thefirst of the slide bars 32 has been scanned by the first of the slots18, and that it shall not be lifted until after that portion of slot 5|,which registers with the last of the slide bars 32, has .been scanned bythe last of the slots 18.

At any time after the slide bar operating levers 36 have been locked,ball 83 may be lifted by its cam 8| to permit the lock levers I8 to beset in accordance with a new signal combination by operation of a keylever. The lifting of lock ball 83 by the operation of the apex of cam8| upon cam follower roll 81 results in release of clutch throwout lever12, so that it returns to the position in which it may effectdisengagement of clutch elements 68 and 69, and also results inclockwise rocking of arm 9| into position to be retained by latch 92. Inthis condition, the lock levers I8 are no longer blocked, and code barsI6 are free to beset in accordance with a new signal combination.However, should a key lever be operated, and through operation ofuniversal ball 22, link I02, lever 98, and sleeve 93, latch 92, berocked clockwise and restored to normal position atthe instant thatlever arm 9| is held in its extreme clockwise position by the apex ofcam 8|, lever arm 9| might not escape from latch 92, and the cycle ofoperation of distributor cylinder 11, intended to be initiatedcorresponding to the combination established by depression of the keylever, would not be initiated and, therefore, a. sig nal combinationwould not be transmitted. To guard against the depression of a key leverat the exact instant that cam follower roll 81 is held at the mostremote position radially of cam 8|, an additional lock is provided uponthe key levers, this lock being effective through the universal bail 22.

Referring particularly to Figs. 2 and 3, it will be observed that alever pivotally supported on pivot rod I2| has arm I22- extending underthe driven sleeve to which driven clutch element 69 is keyed andcarrying at its free end a cam follower roll I23, which engages a camI24 fixed to driven clutch element 69. An arm I28 extends in theopposite direction passing across link I02 near the free or rearmost endthereof, and also passing between upstanding arms I21 of a bifurcatedblock I28, Fig. 3, secured to keyboard base II. At its free end, linkI02 is provided with an upstanding shoulder I29 which must pass throughthe plane in which lever arm I26 is operable in response to operation ofthe universal bail 22 suflicient to effect tripping of clutch throw-outlever 12. Cam I24 normally holds lever arm I26 out of the path ofshoulder I29. Once during a cycle of rotation of cam I24, cam followerroll I23 rides onto a nadir portion of cam I24 and rocks lever arm I28into the path of shoulder I29 of link I02, this operation occurring justprevious to the restoration of lever arm lIlI till

accuses ti by cam ti into position to be retained by latch 32. Lever armI26 remains in the path oi shoulder I 29 until after cam follower rolltil has descended from the apex of cam ti to the extent that unlatchingof lever arm tI by oper ation of link I02 can be effected. Cam followerroll I23 then rides out of the nadir portion of cam IM and lifts leverarm I26 out of the path of shoulder I23. It will be evident from thisthat during the interval in which lever arm I23 is presented in itsextreme clockwise position, link Itt cannot be operated sufiiciently toeffect rocking of latch 32. After the apex of cam ti has cleared latchrestoring cam follower roll 87, lever arm Itt is lifted and link I62 maythen be operated through a full cycle by universal bail it. Bifurcatedblock ltd serves as a guide for the free end of lever arm Itt andprevents link I02 from operating through a full cycle at a time whensuch operation is undesirable.

The electrical circuit for the transmitter hereing described is shownschematically in Fig. 8. By reference to this figure, it will beobserved that the previously identified lamp l3 and motor ti areconnected across conductors ItI and I32 which are intended to beconnected to any suitable source of power, as by means of cord plugIild. Photoelectric cell 54 is connected to the input circuit of anamplifier I34, indicated only symbolically in Fig. 3. For a completedisclosure of an amplifier to which photoelectric cell 54 may beconnected, reference may be had to U. S. Patent No. 2,177,077 granted onOct. 24, 1939, to lb. lI/l. Potts. One of the output terminals ofamplirler I34 may be connected to telegraph line I36 and the other maybe connected to ground. At the remote terminal of line I36 there may beconnected one of the terminals of the selector magnet of a printingtelegraph apparatus indicated symbolically at I37, the other terminal ofwhich may be connected to ground as indicated.

'lihe photoelectric telegraph transmitter herein described is adapted totransmit start-stop permutation code signals each signal combina tionrepresenting a character consisting of a, definite number of impulses ofmarking or spacing nature preceded by a start impulse, usually ofspacing nature, and followed by a stop or rest impulse, usually ofmarking nature. In operation, motor 6| is started, lamp 43 isilluminated, and amplifier I34 is placed in condition to be controlledby photoelectric cell 54. In the rest condition, as previously setforth, slot 19 in cylinder 'I'I registers with slot in cylinder 49 andwith slot 34 in bracket 3|, and as there is no slide bar interposedbetween these slots, light fromlamp 43 impinges upon the cathode 5B ofphotoelectric cell 54 thus rendering the photoelectric cell conductive,and in response to this condition of the photoelectric cell, amplifierI34 applies to line I36 2. continuous marking signal. Mechanicalconditions existing while the rest impulse is being applied to telegraphline I36 are that locking balls 63 and III are held in their uppermostor ineffective positions by latch 92 and cam 82 respectively. The apexof cam 8| is out of the position in which it may prevent the release oflever arm 9| by latch 92, and lever arm I26 is held out of the path ofshoulder I29 carried by link I02.

Upon the depression of a key lever, code bars I6 are shifted to apermutational setting characteristic oi. that key lever. Thispermutational setting is imparted to lock levers I B and near the bottomof the key lever stroke, I111 bail 22 is operated sufiiciently to triped lever arm ti from latch 92 which permits lock bail t3 to be drawndownwardly by spring I03 to hold the lock levers I8 in the positionsinto which they have been moved, and simultaneously de pending armIll'll integral with lock ball 33 trips clutch throw-out lever 12 androtation of cam sleeve It and rotatable cylinder 'II'I begins. as lockbail III was held out of locking position with respect to slide baroperating levers 3% at the time the key lever was depressed, thoselevers followed the motions of lock levers It by reason of theoppositely presented springs 3I and were therefore positionedcorrespondingly to the lush levers It. in the first few degrees ofrotation of driven clutch element 69, lock bail III is low ered by camt2 into locking relation to slide bar operating levers 36 to preventdisturbance of the permutational setting of slide bars M as determinedby the setting of code bars It, Imu ing the lowering of lock bail I I I,the bla por-=- tion of cylinder Il between slot It and the first til ofslots it traverses slot 5i of cylinder td, and

as no illumination reaches the photocell during this traversal, thecurrent through cell ht is re---' duced and possibly entirelyinterrupted, and the condition on telegraph line I36 is changed frommarking to spacing, which is the start condition, and results instarting of printer I3TII.

Depending upon the setting of slide bars tt, certain of them may bepositioned to intercept light transmitted through slot 34 in bracket ti,these being the slide bars that are presented their extreme-left-handpositions, as viewed in Fig. 3, and others may be presented in theirertrerne right-hand positions with their apertures 33 in registry withslots 34 and BI to permit light to impinge uponcathode 56 as thecorresponding slots 78 traverse apertures 33. The rotating cylinder I1thus serves as a transmitting distributor to cause photoelectric cell 54to be rendered conductive or non-conductive a1- ternatively inaccordance with the setting oi the several slide bars 32. Photoelectriccell 54 controls amplifier I34 which, in turn, impresses upon telegraphline I 36 signaling impulses corresponding to the setting of slide bars32. After the last of slots I8 has traversed slot 5|, slot I9, whichrepresents the rest impulse, comes into registry with slot El, and if nokey lever has been depressed during the cycle of operation ofdistributor cylinder I1, it comes to rest upon completion of onerevolution.

In the foregoing paragraph no further reference was made to mechanicaloperations following mention of the lowering of slide bar lever lockingbail I I I, the remainder of the paragraph being devoted to thedescription of the method of generating signal impulses. After lock ballI II has been lowered, lock bail 63 may be lifted, as resetting of thelock levers l8 cannot have any effect upon the setting of slide bars 32.The

' sooner the lifting of lock ball 83 is eflected the greater is theextent of overlap between the transmission of a signal combination andthe setting up of the next signal combination, However, before bail 83 ilifted, cam I24 operates upon its follower roll I23 to lower lever .arrnI26 into the path of shoulder I29 on universal bail link I02 so that theuniversal bail cannot be operated fully during the critical intervalwhen lever arm 9| is being presented under latch 92 and the apex of cam6| is being moved dil out of range of cam follower roll 81. As soon asthese conditions have been satisfied, cam I24 lifts lever arm, I26 andlink I02 is in condition to be operated fully. If at this time anotherkey lever is depressed, the lock levers I8 will be set in a newpermutational arrangement in accordance with the signal combinationrepresented by the key lever, but the slide bar levers 36 being at thistime locked will not be correspondingly moved and certain of the reedsprings 31 will be shifted out of engagement with their slide bar levers36 thus establishing an unbalanced condition which will result insetting of the slide bar levers 36 in correspondence to the setting oflock-levers I8 when near the end of the cycle of rotation of cylinder11, lock bail III shall be lifted. Simultaneously with the lowering oflock bail 83 to store the new setting of the lock levers I8, dependingarm I81 withdraws clutch throwout lever 12 from the path of clutchthrow-out lug 13 so that upon the completion of a revolution cylinder 11will not be arrested but will continue to rotate to achieve thetransmission of the signal combination which had been stored in looklevers I8. Just before reaching the position in which cylinder 11 wouldhave been arrested had the additional signal combination not beenstored, lock bail III is lifted and the slide bars are permitted to beset in correspondence with the positions of lock levers I8, whereuponbail III is again lowered to lock the slide bars 32 in their newpositions. Should another key lever be depressed after the restorationof lever arm 9| and the lifting of lever arm I26, another signalcombination will be stored in the lock levers, and the distributingcylinder 11 will not be arrested at the end of the cycle but willcontinue to rotate to effect the transmission of the signal combinationrepresenting the key lever depressed. As long as an operator continuesto depress key levers during the rotation of cylinder 11, the cylinderwill not be arrested -but will rotate continuously. Cylinder 11 will,however, be arrested after the transmission of the signal combinationcorresponding to the last key lever depressed.

Another embodiment of the invention is shown in Figs. 6 and 7, thisembodiment differing from that already described in the positions of thesource of illumination and of the photo-electric cell and in the furtherfact that there is no provision for overlap as between the transmissionI of a signal combination representing one character and the resettingof the code bars to represent another character.

As indicated in Figs. 6 and '7, motor shaft I4I carries pinion I42meshing with gear I43 fixed to driving clutch portion I44 carried bydistributor shaft I46. Driven clutch element I41 is slidably keyed tocam sleeve I48 also mounted on shaft I46 and is urged into engagementwith clutch driving element I44 by compression spring I49 but isnormally restrained from such engagement and held arrested by clutchthrow-out lever I5I. A slotted distributor cylinder I52 identical withcylinder 11 is rotatably supported by cam sleeve I48, and insidecylinder I52 is mounted a stationary cylinder I53 identical withcylinder 49 and having a single slot I54 parallel to its axis. Thearrangement of elements thus far described is substantially identicalwith those appearing in Figs. 1 to 5, inclusive.

As shown in Fig. 7, a long filament lamp I56 and cylindrical lens I55are mounted inside the stationary cylinder I53, whereby a thin wide beamof light is focussed through slot I58.

Below rotatable cylinder I52 there is mounted a block I51 having aconcave cylindrical surface conformed to the contour of rotatablecylinder I52 and presented in close proximity to the external surface ofthat cylinder. Block I51 has an elongated slot I58 in vertical alignmentwith slot I54 in stationary cylinder I53. Block I51 also has a concavecylindrical surface presented downwardly in conformity with a stationarycylinder I59 which is supported in engagement with the lower concavesurface of block I51 and which has an elongated slot I66 coextensivewith slots I58 and I54 and in vertical alignment with those slots.Cylinder I59 houses a photoelectric cell I6I having a cathode I62. Itwill be apparent that the positions of lamp I56 and photocell I6I could,if desired, be reversed.

Block I51 is provided with a horizontally extending slot of sufficientheight and width to-receive, confine, and guide a plurality of aperturedslide bars I63 substantially identical with the slide bars 32 shown inFigs. 1 and 3. Slide bars I63 are arranged to be presented in either oftwo positions to dispose their apertures correspondingly in or out ofalignment with slot I58 in block I51. Each of the slide bars I63 isarticulated directly to a lock lever I64 pivoted on pivot pin I66supported by keyboard base casting I61. Lock levers I64 are controllablefrom permutation code bars (not shown) in the same manner as thepreviously described lock levers I8 are controlled. There is no yieldbetween lock levers I 64 and slide bars I63 and, therefore, the settingof the lock levers I64 cannot be disturbed until the last of the severalslide bars I63 has been scanned by the corresponding peripheral slot inrotatable cylinder I52.

A single lock bail is provided to prevent disturbance of the lock leversI 64 and slide bars I63 during the transmission of a signal combination,this bail being designated by the reference numeral I68 pivoted onscrews I69, as shown in Figs, 6 and 7. Bail I68 has integral therewithan arm I12 at the free end of which is supported a cam follower roll I13which continuously engages a cam I14 secured to cam sleeve I48. In therest condition of the apparatus, cam I14 holds lock bail I68 out ofblocking relation to upstanding lugs I16 carried at the upper ends oflock levers I64. The operation of lock bail I68 is identical with thatof lock bail III in the previously described embodiment, the bail beinglowered as soon as the distributor cylinder I52 begins to rotate;namely, during the transmission of the start impulse while the blankportion of cylinder I52 is passing across slots I54 and I58 and beinglifted after the last of the slide bar conditions has been scanned bythe last of the peripheral slots, and while the rest impulse slot istraversing slots I54 and I58.

A universal bail link I11 is provided for tripping clutch throw-outlever I5I which is biased to clutch arresting position by spring I15,this link differing from previously described link I02 in that noblocking shoulder corresponding to the shoulder I29 of link I62 isrequired. Link I11 operates a bell crank lever I18 which is similar tothe previously described lever 99 except that it is not associated witha latch controlling sleeve but has instead an arm I19 disposed above andin close proximity to the free end of a rightwardly extending arm I8I ofclutch throw-out lever I5I (as viewed In Fig. 6). Bell crank lever H8 isrocked in the same manner as lever 99 and in being so rocked its arm "9depresses the free end of clutch throw-out lever arm I 6| thus trippingthe clutch and initiating rotation of distributor cylinder I52.

The generation of signal impulses under the control of the setting ofslidebars I63 acting as shutters to control the transmission of light tophotoelectric cell I6I is identical with that dethe cylinder. It followsfrom this that after cylinder I52 has been set in operation bydepression of a key lever, the earliest that the next key lever can bedepressed is just before cylinder I52 completes its cycle of rotationand after the impulses controlled by the several slide bars I63 havebeen generated and transmitted.

No particular disadvantage arises out of the fact that the overlapcontemplated by the first described embodiment of the invention is notpresent in the second as the photo-electric scanning and signalgenerating mechanism is capable of being operated as rapidly as standardcommercially available telegraph printers can receive the signalcombinations and execute the operations in accordance with suchcombinations. The principal difference between the two embodiments ofthe invention from the standpoint of overlap is that the embodimentdisclosed in Figs. 6 and '7, when operated at or near its maximum speed,may require a rhythmic keyboard technique whereas the embodiment shownin Figs. 1 to 5, while not intended to transmit signal combinations anymore rapidly, permits of more irregular keyboard technique, and might bepreferred by operators who at times operate other kinds of keyboarddevices, such as typewriters, andonly occasionally operate a printingtelegraph transmitter keyboard, so that they do not acquire the rhythmictouch.

A further embodiment of the invention is shown in Figs. 10 and 11, thisbeing a modification of the overlap mechanism included in thetransmitter exemplified in Figs. 1 to 5, inclusive. This embodimentdiffers from that of Figs. 1 to in that in the overlap mechanism alreadydescribed, the burden of flexing any number up to five of the springs 31is directly upon the key levers I4, and due to the varying number ofsprings to be flexed, according to the sequence of characters, any keywill require more effort to operate at one time than at another, and thetouch will therefore be irregular, whereas, in the modification to bedescribed, power available within the transmitter is employed forflexing the springs, and none of this labor burdens the keys, so that auniform touch is afforded.

Referring to Figs. and 11, lock levers I9I, connected to code bars I92in the same manner as lock levers I8 are connected to code bars I6 inFigs. 1 and 2, are pivoted on pivot rod I98. Also pivoted on rod I93adjacent to individual lock levers I9I are slide bar controlling leversI94, each of which carries a pin I96 disposed in an elongated slot I91of a light shutter slide bar l98. Slide bars I98 are provided withindividual locl' .ig lugs I99. which are presented on either side of alock bail 20I as slide bars I98 are moved from one to the other of theirtwo possible positions. Lock bail 20I corresponds to lock bail IIIinFigs. 1, 2, and 3.

The upper ends of lock levers I 9I are relatively narrow, and the edgesare substantially parallel to a center line through the levers. Theupper ends of slide bar controlling levers I94 are relatively broad andthe edges slope oppositely from a mid-point thus providing oppositecamming surfaces. Reed springs 202, similar to reed springs 31, arepresented on opposite sides of lock levers I9I and slide bar controllinglevers I94, and at the points of engagement of a pair of springs 202with a lock lever I9I and slide bar controlling lever I94, those leversare of the same width, so that the springs 202 tend to center levers I94with respect to levers I9I.

A single bail 203, corresponding to bail 83,

serves to block lock levers I9I and to operate 2 levers I94. Themovement of a lock lever I9I under control of a code bar I92 need beonly suflicient to present its narrow upper end on either side oftheblade of bail 293. As bail 203 is held elevated when such movementoccurs, there is no restraint on slide bar levers I94, and they followlevers I9I to have their apices presented on either side of bail 203, noflexing of springs 202 occurring during movement of levers I9I and I94by operation of a key lever. The length of slot I91 in each slide barI98 is such that when a slide bar is held in'its extreme lefthandposition, as in Fig. 10, movement of its associated lever I94 clockwiseby a lock lever I9I will result in presentation of its pin I96substantially in the right-hand end of the slot I91. Conversely, when aslide bar is held in its righthand position and its associated operatinglever I94 is presented counterclockwise bya lock lever I9I, the pin I96is brought substantially into engagement with the left-hand end of theslot.

When a slide bar operating lever I94 has been shifted by its associatedlock lever I9I, as for example, in clockwise direction, its associatedslide bar I98 being held locked by bail I, as shown in Fig. 10, it comesto rest with its pin I96 substantially prepared to impart rightwardmovement to slide bar I98 and with a portion of the left-hand slopingsurface of its broad head in the path of bail 203. The bail may descend5 only until it is arrested by lever I94 assuming that lug I99 of slideI98 continues to be blocked by bail 20I. No further clockwise movementis imparted to lock lever I9I by descending bail 203. The tension springby which bail 203 is urged downwardly, which corresponds to spring I09of Fig. 1, exerts greater force than the aggregate of force exerted byfive or less of the springs 202, and as soon as bail 20I is lifted, bail293 descends the remainder of the distance it is intended to move. Thefurther descent of nail 203 produces a camming effect upon the slopingsurface of the head of lever I94, which is thus moved further clockwiseand which, through its pin I96, shifts slide bar I98 to its right-handposition. The further clockwise movement of lever I94 causes it to drawaway from left-hand spring 202 and to draw right-hand spring 202 awayfrom lever I9I, thus tensioning the springs, as shown in Fig. 11.

Looking of slide bar I98 in the new position; namely, its right-handposition, as viewed in Fig. 11, is accomplished. when bail 20I islowered to its dotted line position into the'path of lug I99.

Thereafter bail 203 ma be lifted and when it 75 is lifted, springs 202restore lever I94 to centered position with respect to lever I 9|, pinI96 thus being moved away from the right-hand end of slot I91. When theslide bar I98 is to be restored to its left-hand position, lever I 9| isrocked counterclockwise, whereby pin I96 is presented in the extremeleft end of slot I91, and as bail 293 descends and bail MI is lifted,slide bar I99 is shifted leftwardly by bail 293 operating through leverI94 and pin I96.

From the foregoing, it will be apparent that after the slide bars I98have been locked, lock levers I9I and slide bar operating levers I94 maybe unlocked and reset according to a new signal combination. Slide baroperating levers I94 are not locked during the transmission of a signalcombination, as in the embodiment first described but onlyslide bars I99are so locked. Furthermore, whereas reed springs 91 in the firstdescribed embodiment operate to set the slide bars 32 according to thesetting of lock levers l8, in the embodiment shown in Figs. 10 and 11,the tension spring (not shown) which lowers bail 203 shifts the slidebars I98, and springs 202 operate subsequently to restore the slide baroperating levers I94 to alignment with the lock levers I9l, suchrestoration being attended by idle movement of pins I96 within the slotsI91 of the then stationary slide bars I98.

Although particular embodiments of the invention have been disclosed anddescribed herein, it is to be understood that the invention is notintended to be limited to such embodiments but is capable ofmodification, rearrangement, and substitution without departing from thespirit of the invention and within the scope of the appended claims.

What is claimed is:

1. In a telegraph transmitter adapted to be controlled by a keyboarddevice, a key lever op- ,erated selector mechanism, a plurality of lightshutters controlled by said selector mechanism. a photoelectronicimpulse generator, and means for scanning said light shutters to controlsaid impulse generator.

2. In a telegraph transmitter adapted to be controlled by a keyboarddevice, a key lever operated selector mechanism, a plurality of lightshutters controlled by said selector mechanism, a photoelectronicimpulse generator, and a rotatable scanning member having an aperture inalignment with each of said light shutters for controlling said impulsegenerator.

3. In a telegraph transmitter adapted to be controlled by a keyboarddevice, a key lever operated selector mechanism, a plurality of lightshutters controlled by said selector mechanism, a photoelectronicimpulse generator, and a rotatably mounted cylindrical scanning memberhaving a circumferential aperture in alignment with each of said lightshutters for controlling said impulse generator.

4. In a telegraph transmitter adapted to be controlled by a keyboarddevice, a key lever operated selector mechanism, a plurality of lightcontrolled by a keyboard device, a key lever controlled selectormechanism, an impulse generating mechanism, means controlled by saidselector mechanism for controlling said impulse generating mechanism,means for locking said selector mechanism upon the operation thereof,means for locking said selector controlled means, and means forunlocking said selector means after the locking of said selectorcontrolled means and during the generation of impulses under the controlof said locked selector controlled means.

6. In a transmitting device, a keyboard including a plurality of keys, aset of permutation bars controlled by said keys, 8. transmittingcircuit, photoelectric signal generating means connected to saidcircuit, and means controlled according to the operation of saidpermutation bars fordetermining the signals to be generated by saidphotoelectric means.

7. In a transmitting device, a plurality of selectively operable keys,9. set of permutation bars controlled by said keys, a photoelectricinstrumentality, means controlled according to the operation of saidpermutation bars for controlling the action of the photoelectricinstrumentality, and means for transmitting code signals according tothe action of the photoelectric instrumentaiity.

8. In a telegraph transmitter, a plurality of selectively operable keys,a plurality of light shutters, a photoelectric device, means controlledby the keys for operating said shutters in varying permutations, andmeans for controlling said photoelectric device in accordance with theoperation of said shutters to eflect the transmission of code signals.

9. In a photoelectric transmitter, a plurality of light shutters, keyoperated means for effecting the permutational setting of said shutters,and means including a photoelectric device for transmitting start-stoptelegraph signals according to the control of said light shutters.

10. In a photoelectric transmitter including a plurality of keys, amaster light shutter, a plurality of secondary light shutters, means foroperating the master shutter invariably upon the operation of any key,means for operating the secondary shutters variably according to the keyoperated, and photo-sensitive means for generating code signalsaccording to operation of the secondary shutters.

11. In a photoelectric signal transmitter, a light shutter device fordetermining the character of the signals, a light shutter device fortiming the elements of the signals, selector mechanism for operating thefirst mentioned shutter device variably, and means for operating thelast mentioned shutter device invariably.

12. In a photoelectric signal transmitter, a variably operable lightshutter device, an invariably omrable light shutter device, means forvariably controlling the flrst mentioned light shutter device, and meansassociated with the last mentioned means for initiating operation of thesecond mentioned shutter device.

13. ,In a telegraph transmitter, a keyboard mechanism including aplurality of keys, permutation bars controlled by said keys, primarysignal controlling means controlled by said permutation bars, secondarysignal controlling means controlled by said primary means, means forlocking said primary and secondary means successively, and means forunlocking said primary means substantially immediately after the lockingof said secondary means.

lid

ii. In a telegraph transmitter, a keyboard mechanism including aplurality of keys, permutation bars controlled by said keys, primarysignal controlling means controlled by said permutation bars, secondarysignal controlling means controlled by said primary means, independent1y operable locking means for said primary and secondary signalcontrolling means, and yieldable means interconnecting said primary andsecondary means for affording movement of either of said primary andsecondary means while the other is locked for a particular signal to betransmitted.

15.1111 a telegraph transmitter, a keyboard mechanism including aplurality of keys, code bars controlled by saidkeys, primary signalcontrolling means controlled by said code bars, secondary signalcontrolling means controlled by said primary means, and yieldable meansfor biasing said secondary means to follow the movement of said primarymeans whereby signals in accordance therewith may be transmitted.

l6. In a telegraph transmitter, a keyboard mechanism including aplurality of keys, code bars controlled by said keys, a rotatable signaldistributor, key controlled means for releasing said distributor forrotation to transmit signals in accordance with the setting of said codebars, means for locking said key controlled means upon operationthereof, cam operated means for restoring said locking means tounoperalted condition, and means for locking said key controlled meansduring the restoration of said first mentloned locking means.

17. In a telegraph transmitter, a keyboard mechanism including aplurality of keys, code bars controlled by said keys, a rotatable signaldistributor, a keyoperaited universal bail, means controlled by saidbail for releasing said distributor for rotation to transmit signals inaccordance with the setting of said'code bars, means for locking saidball upon operation thereof, means associated with said distributor forrest-oring said locking means to unoperated condition, and means alsoassociated with said distributor for imposing a locked condition uponsaid bail during the restoration of the first mentioned locking means.

18. In a telegraph transmitter, a keyboard mechanism including aplurality of keys, a universal bail operable 'bysaid keys, a pluralityof code bars also operable by said keys, means operable by said bail forlocking said code bars, a signal distributor, and means operable by saidlocking means for setting in operation said distributor whereby signalsin accordance with the operation of said bars will be transmitted.

19. In a telegraph transmitter, a keyboard mechanism including aplurality of keys, code bars to be set permutatively by said keys, aplurality of levers articulated to said code bars, a.

plurality of levers capable of being held stationary while the firstmentioned levers are set by the code bars, a plurality of impulsecontrolling elements articulated to the second mentioned levers, andflexible members associated with said first and second mentioned leversand adapted to be distorted upon set-ting of the second mentioned leversWhile the first mentioned levers are held stationary, and to effectmovement of said second mentioned levers upon release of the holdthereon.

20. In a telegraph transmitter, a keyboard mechanism including aplurality of keys, code bars to be set permutatively by said keys, aplurality of levers articulated to said code bars, a plurality of leversindividually associated with the first mentioned levers, flexiblemembers for causing the second mentioned levers to follow movement ofthe first mentioned levers, a plurality of impulse controlling elementscontrolled by said second mentioned levers, and means operable by powerindependent of said keys and set in operation by said keys for movingsaid second mentioned levers through distances greater than thoseimparted by said first mentioned levers.

21. In a telegraph transmitter adapted to be controlled by a keyboarddevice, a photo-electric impulse generator, means for producing a lightbeam, means controlled variably by said keyboard device for dividing aportion of said beam of light into corresponding individual beams oflight, and means operated invariably by said keyboard device foradmitting to said photo-electric impulse generator a portion of theremainder of said first mentioned light beam and the individual lightbeams in predetermined succession.

22. In a telegraph transmitter adapted to be controlled by a keyboarddevice including a plurality of key levers, a permutation codedevicecontrolled by said key levers, a photo-electric impulse generator,means for producing a beam of light, means controlled permutably by saidpermutation cod device for preparing variable light paths from said beamto said photo-electric impulse generator, and means operated invariablyby said keyboard device for completing said light paths.

23. in a telegraph transmitter adapted to be controlledby akeyboarddevice, aperm'utationcode device responsive directly to saidkeyboard device, means ior producing a light health, a photoelectricimpulse generator, means having light transmitting apertures fordistributing light to said photo-electric impulse generator, and meanspermutably controlled by said permutation code device for transmittingto the surface of said distributlng means light from said beam invariably disposed areas.

24-. In a telegraph transmitter adapted .to be controlled by a keyboarddevice, impulse generating means, impulse distributing means, a timingelement controlled by said keyboard device, a timing element controlledby said distributor, and means controlled by said timin elements forcoordinating the operation of said keyboard device and saiddistributingmeans.

25. In a telegraph signaling apparatus, signal transmitting means, a setof elements, a set of selectors corresponding in number to saidelemenits, means operated permutably by said selectors for setting saidelements correspondingly, a source of light, a power driven rotarymechanism cooperating with said elements in the operation of saidtransmitting means by light from said source, and means for setting saidselectors.

26. In a telegraph signaling apparatus, signal transmitting means, a setof elements, a set of selectors corresponding in number to saidelements, means operated permutably by said selectors for setting saidelements correspondingly, a source of light, a power driven rotarymechanism arranged for uniformly rendering said source of lighteffective on said transmitting means to controlthe length of each signalimpulse transmitted thereby, and means for setting said selectors.

27. In a telegraph signalling apparatus, signal transmitting means, aset of elements, a set oi selectors corresponding in number to saidelements, means operated perm-utably by said selectors for setting saidelements correspondingly, a source of light, a power driven rotarymechanism having means for uniformly rendering said source of lightefiective at the beginning of each signal, and means for successivelyrendering the source of light efieotive on said transmitting means asdetermined by the position of said elements.

28. In a telegraph signaling apparatus, signal transmitting means, a setof elements, a set of selectors corresponding in number to saidelements, means operated permutably by said selectors for setting saidelements correspondingly, a source of light, a power driven rotarymechanism cooperating with said elements in the operation of saidtransmitting means by light from said source, means to start said rotarydriven mechanism at the beginning of each signal, means to stop the sameat the end of each signal, and a keyboard for controlling said startingand stopping means and for setting said selectors.

29. In a telegraph signaling apparatus, signal transmitting means, a setof elements, a set of selectors corresponding in number to saidelements, means operated permutably by said selectors for setting saidelements correspondingly, a source of light; a rotary power drivenmechanism cooperating with said elements in the operation of saidtransmitting means by light from said source, a start and stop clutchfor rotating and timing the operation of said mechanism during eachsignal period, a keyboard for tripping said clutch and for setting saidselectors, and a lock for said keyboard controlled by said mechanism andarranged to release said keyboard for reoperation at the end of eachsignal period.

30. In a signaling apparatus, signal transmitting means for controllingall transmitted impulses, a set of elements for controlling theoperation of said transmitting means, a set of selectors, means operatedpermutalbly by said se- 5 lectors for setting said elementscorrespondingly, a source of light, a rotary driven mechanism having aseries of successively operating sections cooperating withsaid elementsin the operation of said transmitting means by light from said .0 sourcein accordance with the position of said selectors, a power driven startand stop clutch for continuously advancing and timing the operation ofsaid rotary mechanism during each signal period, a keyboard, and meansoperated 55 thereby independently of said transmitting means fortripping said clutch and for operating said selectors.

31. In a signaling apparatus, signal transmitting means, a set ofselectors, a source of light, a rotary member having a series ofsuccessively operative sections for eflecting th operation of saidtransmitting means by light from said source of light to transmituniform starting impulses followed by a series of selecting impulsesvaried 5 in accordance with the setting of said selectors,

a power driven start and stop clutch for rotating said rotary member,and means independent of said transmitting means for tripping saidclutch and setting said selectors.

32. In a telegraph transmitter, a keyboard mechanism including a.plurality of keys, code bars controlled by said keys, a rotatabledistributor, key controlled means for releasing said distributor forrotation to transmit signals in accordance with the setting of saidbars, means controlled by said code bars for controlling the characterof the signals transmitted by said distributor, means for locking saidkey controlled means upon operation of said distributor, and means forthereafter locking said code bar controlled means and releasing said keycontrolled means whereby they may be reset.

33. In a photo-electric signal transmitter, a light shutter devicepermanently associated with said transmitter for determining thecharacter of the signals, a light shutter device for timing the elementsof the signals, means for operating the first mentioned light shutterdevice variably, and means for operating the last mentioned shutterdevice invariably.

34. In a telegraph transmitter, a keyboard mechanism including aplurality of keys, permutation bars controlled by said keys, primarysignal con-trolling means controlled by said bars, latch controlledmeans for locking said signal controlling means, secondary signalcontrolling means controlled by said primary signal controlling means,cam controlled means for locking said secondary signal controllingmeans, and means for unlocking and relatching said latch controlledlocking means following the locking of said secondary signal controllingmeans.

35. In a telegraph transmitter, a keyboard mechanism including aplurality of keys, permutation bars controlled by said keys, primarysignal controlling means controlled by said bars, means for locking saidprimary signal controlling means, m-eans for latching said locking meansin unlocking position, means controlled by said keys ,for releasing saidlatching means, secondary signal controlling means controlled by saidprimary signal controlling means, means for locking said secondarysignal controlling means, rotatable cam means for operating said lastmentioned locking means, and rotatable cam means for relatching saidfirst mentioned looking means following the operation of the secondmentioned locking means to lock said secondary signal controlling means.

36. In a telegraph transmitter adapted to be controlled by a keyboarddevice, a key lever controlled mechanism, an impulse generatingmechanism, means controlled by said key lever controlled mechanism forcontrolling said impulse generating mechanism, means for locking saidkey lever controlled mechanism, means for locking said impulsegenerating mechanism controlling means, and cam controlled means foroperating both of said locking means in a predetermined sequentialmanner whereby said key lever controlled means is released before saidimpulse generating mechanism controlling means.

37. In a telegraph transmitter adapted to be controlled by a keyboarddevice, a key lever controlled mechanism, an impulse generatingmechanism, means controlled by said key lever controlled mechanism forcontrolling said impulse generating mechanism, primary means for lockingsaid key lever controlled mechanism, means for locking said impulsegenerating mechanism controlling means, means for releasing said primarylocking means, secondary locking means for said key lever controlledmechanism, and means for operating said secondary locking means prior tothe release of said primary means and for releasing said secondary meansafter the release of said primary means.

LOUIS M. POTTS.

